add requests to requirements.txt (#3113)

The backends were exiting due to missing `requests`


![image](https://github.com/LAION-AI/Open-Assistant/assets/4523694/4a5b0057-c8b5-4cc4-982c-5b699cfa4910)

Author: ComradeEcho

backend/requirements_worker.txt

@@ -14,6 +14,7 @@ pydantic[email]==1.9.1
 python-dotenv==0.21.0
 python-jose[cryptography]==3.3.0
 redis
+requests
 scipy==1.8.1
 SQLAlchemy==1.4.41
 sqlmodel==0.0.8